200;
TEI-838
UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY
CHEMISTRY AND MOVEMENT OF GROUND WATER,
NEVADA TEST SITE*
By
~ :^
Stuart L. Schoff and John E. Moore
1964
REPORT TEI-838
This report is preliminary
and has not been edited for
conformity with Geological
Survey format.
^Prepared on behalf*of the
U.S. Atomic Energy Commission
CONTENTS
Page
Abstract
-
*--
*
Introduction
7
Purpose and scope
Acknowledgments---------------
8
-*
<fc 8
Location and area
8
Topography and drainage
8
General geology
General hydrology
Previous investigations
This investigation
Numbering system
10
' 12
-
13
-
14
15
Water types
16
Relation of water chemistry to rock types
19
Water from tuff
19
Water from carbonate rocks
21
Water from alluvium
22
Water from granodiorite
24
Unusual water types
25
Water of mixed type from tuff
25
Water high in sulfate
25
Water high in sulfate and in dissolved solids
26
High sodium in calcium-magnesium area
28
Unlike water from adjacent wells
29
CONTENTS Continued
Page
Water from springs and from tunnels
34
Chemical character of ground water by areas
36
Indian Spring Valley
36
Frenchman and Yucca Flats
39
Jackass Flats (including Rock Valley)
42
Amargosa Desert
45
Water movements inferred from dissolved solids
52
Water movements inferred from sodium distribution
59
Summary and conclusions -
-
-
- -
References cited
Appendix A.
61
64
Chemical analyses of water, in parts per million
and equivalents per million (in parentheses), of well
waters from the Nevada Test Site and vicinity, by
the U.S. Geological Survey
Appendix B.
-
-
67
Selected chemical analyses of waters from springs
and tunnels, in parts per million and equivalents per
million (in parentheses), by the U.S. Geological
Survey---------------------
73
ILLUSTRATIONS
Page
Figure I.
Map of the Nevada Test Site and vicinity showing
the distribution of principal rock types and
the chemical character of the ground water
2.
Index map showing principal places discussed in
this report --
3.
pocket
----
-
-
9
Chemical diagrams representing three types of
water, Nevada Test Site and vicinity
4.
Chemical diagrams representing water
and tunnels in tuff, and waterf
5.
18
from springs
from granodiorite
20
Chemical classification, in percent of total
equivalents per million, of water from Indian
Spring Valley, Yucca and Franchman Flats, and
Jackass Flats (including Rock Valley)
6.
-
Map of the southwestern part of the Amargosa
Desert, showing chemistry of ground water-
7.
37
46
Map of the southwestern part of the Amargosa
Desert showing the distribution of calcium plus
magnesium in ground water,
of total cations.
expressed as percent
Area covered and water sources
are the same as in figure 6-
-
50
TABLES
Page
Table 1.
Analyses of water from wells 66-69 and 68-69,
in parts per million and equivalents per
million
2.
27
Principal ions in water
from wells 79-69a and
79-69b, in equivalents per million
3.
32
Calcium and bicarbonate in water from wells 79-69a
and 79-69b
4.
34
Composition in percentages of chemical equivalents
of cations and anions of water from Indian Spring
Valley
5.
38
Composition in percentages of chemical equivalents
of cations and anions of water from Frenchman
and Yucca Flats
6.
.......... .....
40
Composition in percentages of chemical equivalents
of cations and anions of water from Jackass Flats
(including Rock Valley)
7.
44
Composition in percentage of chemical equivalents
of cations and anions of water from the Amargosa
Desert?*
8.
-
-
Dissolved solids in spring water,
Nevada Test Site,
in parts per million
9.
47
53
Variations in dissolved solids at Whiterock Spring,,
Nevada Test Site, in parts per million
-
53
CHEMISTRY AND MOVEMENT OF GROUND WATER,
NEVADA TEST SITE
by
Stuart L. Schoff and John E. Moore
ABSTRACT
Three chemical types of ground water are distinguished at the Nevada
Test Site and vicinity.
A sodium-potassium water is related to tuff (in
part zeolitized) and to alluvium containing detrital tuff.
A calcium-
magnesium- water is related to limestone and dolomite, or to alluvium
containing detritus of these rock types.
A mixed chemical type, con-
taining about as much sodium and potassium as calcium and magnesium,
may result from the addition of one of the first two types of water to the
other; to passage of water first through tuff and then through carbonate
rock, or vice versa; and to ion-exchange during water travel.
Considera-
tion of the distribution of these water types, together with the distribution of sodium in the water and progressive changes in the dissolved
solids, suggests that the ground water in the Nevada Test Site probably
moves toward the Amargosa Desert, not into Indian Spring Valley and thence
southeastward toward Las Vegas.
The low dissolved solids content of
ground-water reservoirs in alluvium and tuff of the enclosed basins
indicates that recharge is local in orgin.
7
INTRODUCTION
The chemical character of ground water depends to a large degree
upon the character of the rock formations through which the water moves,
The composition of the water is the result of several solutional and
decompositional processes.
Certain reactions, such as the solution
of carbonate, and the exchange of cations, are reversible.
The chemical
processes are affected by certain variables in the environment, among
them the type of geologic environment, amount of vegetative cover,
amount of water available, its rate of circulation, the activity of
micro- and other organisms, temperature, and pressure.
The chemical constitution of a sample of ground water is a history
of the underground experiences of the water.
Yet, the deciphering of
that history is often made impossible by sheer complexity.
The longer
the water is underground and the greater the number of geologic environments through which it passes, the more complicated and difficult to
unravel is its history.
A large number of water samples from the Nevada Test Site and
vicinity has been analyzed in the course of hydrologic investigations
by the Geological Survey in behalf of the U.S. Atomic Energy Commission,
Others have been analyzed in connection with investigations made in
cooperation with the Nevada State Engineer.
These analyses clarify
some questions regarding the movement of ground water from the Test
Site.
8
Purpose and scope
The purpose of this report is to determine if the chemical character
of the ground water can be used to predict the direction of groundwater movement from the Nevada Test Site.
The report describes the
chemical variation of ground water in different basins and relates these
variations to aquifer lithology and ground-water movement.
.Acknowledgment s
The writers wish to express their gratitude to their colleagues of
the U.S. Geological Survey who have offered many helpful suggestions and
criticisms.
Special thanks are due J. D. Hem and R. C. Scott for
constructive advice on geochemistry and for critical review of this
report.
None of these men, however, should be held responsible for
the authors 1 interpretations and conclusions.
Location and area
The Nevada Test Site is an approximately rectangular area of
about 1,130 square miles in southern Nye County, Nev., and is about
70 miles northwest of Las Vegas, Nev.
The geologic map illustrating
this report (fig. l) extends beyond the boundaries of the Test Site
on all sides and represents about 2,200 square miles.
Places mentioned
in this report but beyond the limits of figure 1 are shown in figure 2.
Topography and drainage
The Nevada Test Site is in the Basin and Range physiographic
province.
It contains two enclosed basins, Yucca Flat and Frenchman
Flat, one basin having exterior drainage, Jackass Flats, and several
mountain ranges.
37°30'
37°
36°30'
DEATH VALLEY
JUNCTION
SCALE IN MILES
Figure 2.--Index map showing principal places discussed in this report
(Base from World Aeronautical Chart 3°3> Mt Whitney.)
10
The western part of the Test Site is drained by Fortymile Canyon
into Jackass Flats, which in turn is drained southward into the Amargosa
Desert.
The Las Vegas Valley,' an intermontane trough, trends southeastward
from the southern end of the Test Site to Las Vegas.
It is flanked on
the southwest side by the Spring Mountains and on the northeast side
by the southern ends of several mountain ranges.
half of it is drained toward Las Vegas.
Only the southeast
The rest is drained into
playa lakes in the southern ends of Indian Spring and Three Lakes
Valleys.
General geology
The mountains are composed of sedimentary rocks of late Precambrian and Paleozoic age and of extrusive and minor sedimentary rocks
of Tertiary or younger age.
The rocks of Paleozoic age have been
intruded by granitic rocks of Mesozoic age (Houser, F. N., written
communication, 1963)
Both the sedimentary rocks of Paleozoic age
and the rocks of Tertiary or younger age have been intruded by mafic
dikes of Miocene or younger age.
The basins are partly filled with
unconsolidated alluvial and lacustrine sediments.
The upper parts of
these sediments are of Quaternary age, but the lower parts at places
may be of Tertiary age.
The total stratigraphic thickness of the late Precambrian and
Paleozoic rocks is more than 35*000 feet, somewhat more than half of
which is limestone and dolomite (Barnes, Harley, oral communication,
1963)
The limestone and dolomite are especially important in both
the circulation and the chemistry of the ground water.
They will be
11
referred to collectively hereafter as the carbonate rocks.
The other
principal rock types in the Paleozoic sequence are siltstone, argillite,
and quartzite.
The rocks of Tertiary or younger age consist principally of tuff
but include also flows of basaltic, andesitic, and rhyodacitic composition, together with minor amounts of sedimentary rocks.
Their total
aggregate thickness is not known, but it probably exceeds 10,000 feet
(Healey and Miller, 1962, p. 9).
The volcanic rocks have been penetrated
in drill holes to a depth of more than 5,000 feet.
Most of these rocks
are rhyolitic (Houser, F. N., and Botinelly, T., oral communication,
1963)
Despite considerable variation in physical appearance, they
are a unit in their effect on the chemistry of the ground water.
The zeolitized parts of the tuff are especially important because they
influence the chemical character of the water through ion-exchange.
The valley fill (alluvium) is thick in some of the basins.
The
maximum known thickness of the fill is 1,870 feet, in south-central
Yucca Flat, where it was penetrated in a test well.
The well was not
drilled to the bottom of the fill, however, and the complete thickness
was not determined.
The al-luvium is composed of detritus from the
adjacent mountains, and the character of the water in it depends on
the kinds of rock materials in it.
The geologic structure is extremely complex.
As stated by Healey
and Miller, (1962, p. 10), "The Paleozoic rocks were extensively thrust
faulted, probably during the Late Cretaceous (Johnson and Hibbard,
195T> P- 378)-
Many normal faults displace both the Paleozoic sedi-
mentary rocks and the Tertiary volcanic rocks.
Vertical displacements
12
on the normal faults range from a few feet to several thousands of
feet.
The Las Vegas Valley shear zone (Longwell, 1960) has had profound
influence on the present structure of the southeast part of the region.
This major shear zone may be traced 100 miles northwestward from Boulder
City, Nev. * * *.
Horizontal movement along the shear zone has been
estimated at 25 miles by Longwell (1960) and 27 miles by B. C. Burchfiel
(written communication, 1961)."
General hydrology
The chemical character of ground water is the result of processes
during the movement of the water from places of recharge to places of
discharge.
Ground water in the Basin and Range province is recharged
from precipitation, principally on the flanks of the mountains.
It
then moves down into the valley fill, whence it discharges by evapotranspiration.
The bedrock that makes up the mountains and underlies
the fill was thought to be an impermeable barrier that prevents the
movement of ground water from one basin to another.
This seems not to
apply to the basins of the Nevada Test Site and several other basins
in southern Nevada.
Winograd (l962a, p. 8; 1962b, p. Clio) has shown
that water levels in wells in the Tertiary tuff decline as the wells
are deepened into the zone of saturation.
The head in the tuff is
higher than that in the underlying Paleozoic carbonate rocks at the
same place.
He concludes, "The movement of ground water in the valley
fill and the tuffs beneath the bolsons of the Nevada Test Site is
vertically downward into the Paleozoic carbonate rocks.
The ground
water moves laterally in the carbonate rocks, though probably circuitously,
beneath all three basins toward the discharge areas, presumably to the
southwest."
13
Eakin and others (1963) have shown that, in a region extending
from the California state line northward nearly 90 miles beyond the
Nevada Test Site, the ground water may move from north to south.
The
hydraulic potential, as represented by the water-level altitudes in
selected wells, and the relations of discharge to recharge suggest that
southward movement is not only possible but probable.
Confirmation of
this movement is suggested by the chemical character of the waters.
The ground water probably is discharged in the Amargosa Desert and, in
part, in Death Valley.
Previous investigations
Reference has been made in the preceding section to significant
reports that have been published on regional hydrology.
Other sources
of information, especially data on chemical character of water, are
mentioned below.
Chemical analyses of water samples collected in tunnels driven
into Rainier Mesa at the northwest border of Yucca Flat were reported
by Clebsch and Barker (1960), and those for waters from wells, test
holes, and springs in and near the Nevada Test Site to 1960 were
reported by Moore (1961, tables 3 and 5)-
Five of the analyses for
the Nevada Test Site and several for water from surrounding areas
were reported also by Scott and Barker (1962, p. 72-73).
The analyses
of water from the test wells drilled for the Geological Survey*s
hydrologic investigation of the Nevada Test Site have been reported in
various Survey TEI reports summarizing the results from the individual
wells, have been tabulated by Eakin and others(1963)> and are repeated
in appendix A of this report.
The tritium age of ground water as
related to the movement of the water in and near the Nevada Test Site
was discussed by Clebsch (1961).
THIS INVESTIGATION
Most of the chemical analyses given in this report were made by
the Quality of Water Branch, U.S. Geological Survey, Denver, Colo.
A few analyses were made in other Survey laboratories, or in outside
laboratories.
The water samples were collected by many individuals,
most of them Survey personnel.
The analyses were evaluated in relation to drilling methods and
to conditions in the wells at the time of sampling, and eight that
probably do not represent the formation water have been excluded from
the maps and tables in this report.
Among these are samples that have
a pH of 9»9 t° 11-5» which probably is due to cement that was used in
the well.
A few others represent samples that probably had been con-
taminated by, or consisted mainly of, drilling fluid.
The analyses were plotted for study as modified pie diagrams,
which in the form adopted here facilitate the discrimination of borderline water types and represent fairly well the chemical concentration.
These diagrams appear in several of the illustrations for this report.
Nearly all those for well water appear on figure 1.
The water of springs and that from fractures intersected in the
tunnels in Rainier Mesa are discussed in the text and tabulated in
appendix B but are not illustrated by diagrams in figure 1.
These
water types are from perched zones of saturation and therefore do not
represent regional ground-water trends.
The spring water and some of
the tunnel water is diagramed in figure 4.
15
Parallelogram diagrams also were used in the study of the chemical
analyses, because these diagrams facilitate comparison of the water of
one area with that of another (Piper, 19^5)
They may show progressive
change in chemical composition in one direction or another, and
thereby may suggest the direction of movement of the water.
On
these diagrams the percentage of sulfate, chloride, fluoride, and
nitrate are plotted against bicarbonate and carbonate on one axis, and
calcium and magnesium are plotted against sodium and potassium on the
other axis.
Parallelogram diagrams for ground water from several areas
in and adjacent to the Nevada Test Site are shown in figure 5»
The analyses tabulated in appendices A and B of this report are
stated in both parts per million (ppm) and equivalents per million
(epm).
The figures for epm are used in plotting the pie diagrams
and in calculating percentages for the parallelogram diagrams.
Numbering system
Wells, test holes, and springs are identified in this report by
location numbers based on the Nevada State coordinate system, central
zone.
Each number consists of at least two parts: the first two digits
of the north coordinate, followed (after a hyphen) by the first two
digits of the east coordinate.
Where several wells are in the same
10,000-foot rectangle, a letter is added to the number for each well,
beginning with "a."
The well, test hole, or spring is always on or
north of its north coordinate and on or east of its east coordinate.
The coordinates shown on the map (fig. l) are 64(0,000) at the
south to 94(0,000) at the north; and 56(0,000) at the west to 77(0,000)
at the east.
A location number that is low in both digits--73-58, for
16
example is in the southwestern part of the map.
A location number that
is high in both digits--91-7^> f°r example--is in the northeastern part
of the map.
Wells and springs in the Amargosa Desert have been numbered by
the Ground-Water District Office, U.S. Geological Survey, Carson City,
Nev., according to township, range, and section.
This arrangement could
not be extended into the Nevada Test Site because townships and sections
have not been surveyed there.
For uniformity in this report, therefore,
the wells and springs of the Amargosa Desert have been assigned numbers
based on the coordinate system, which for convenience has been extended
arbitrarily into the California part of figure 6.
WATER TYPES
The ground water of the region is bicarbonate water with but few
exceptions.
Some of the water from the Test Site is sulfate water.
One water has nearly as much sulfate as bicarbonate.
The circumstances
that seem to account for these and a few others are discussed in the
section headed "Unusual water types."
Most of the water can be classified on. the basis of cations alone
as follows:
1.
Sodium-potassium type sodium predominates, potassium generally
is minor to negligible and the two together are 60 percent or more of
total cations.
2.
Calcium-magnesium type either calcium or magnesium may pre-
dominate, and the two together are 60 percent or more of total cations.
3*
Mixed chemical type neither cation pair amounts to as much as
60 percent of total cations; both pairs amount to more than IjO percent
17
each, and either pair may predominate.
When plotted as modified pie diagrams, these three water types are
fairly distinctive.
The sodium and potassium are plotted together in
the southeast quadrant, and opposite in the northwest quadrant the
calcium and magnesium are plotted together.
The bicarbonate and
carbonate are plotted together in the northeast quadrant and the
sulfate and chloride are .plotted together in the southwest quadrant
(fig. 3).
A sodium-potassium water approximates a semicircle in the east
half of the diagram, but a calcium-magnesium water approximates a
semicircle in the north half (fig. 3» wells 84-68 and 65-?3> respectively).
A water of mixed chemical type generally has a relatively large wedge
in the northeast quadrant, and smaller, more or less equal, wedges in
the northwest and southeast (fig. 3» well 75~73)« If the mixture also
includes sulfate and chloride in substantial proportions, there will
be a wedge in the southwest, and the diagram will approach a circle.
The term, "mixed chemical type," is not intended to mean that
turbulent mixing of waters has taken place.
Turbulent mixing seems
unlikely to occur underground except in special geologic situations,
such as large solution openings.
A water of mixed chemical type may
be attributed to passage of the water through one kind of rock and then
another, with opportunity for ion exchange or solution of different
minerals.
As suggested above, most of the water of the region is low in
sulfate and chloride.
Many of the pie diagrams show almost nothing in
the quadrant assigned to these anions.
18
Calcium-magnesium water
(well 65-73)
Sodium-potassium water
(well 84-68)
Water of mixed chemical type
(well 75-73)
Plotting scheme
and scale (in equivalents per million)
Figure 3»--Chemical diagrams illustrating three types of water, Nevada
Test Site and vicinity.
19
RELATION OF WATER CHEMISTRY TO ROCK TYPES
The relation of the chemical composition of the ground water
to rock types is shown by figure 1, on which the chemical diagrams are
placed adjacent to the symbols representing the source of the water,
and the geology is represented by rock types rather than by geologic
formations.
Some wells tap strata other than and different from the
rock at the surface, thus obscuring the relation of water to aquifer.
Well 88-66 begins in alluvium but draws water from carbonate rock.
Wells 73*66 and 87-62 tap both tuff and carbonate rock, and analyses
for both water sources are shown.
A letter adjacent to the chemical
diagram indicates the lithology of the aquifer.
Water from tuff
f
Water from volcanic rocks--mainly tuff--is typically a sodiumpotassium water that contains but little calcium, magnesium, sulfate,
or chloride.
The water collected from seeps in the tunnels in Rainier
Mesa and the water from springs probably have traveled only or mainly
through tuff and are considered to be typical of water from tuff
(fig. k) .
Some of this water contains small amounts of calcium,
magnesium, stflfate and chloride, indicating that these constituents
are not entirely lacking in the tuff.
The water of some springs
contain enough of these constituents so that they may be classed as
of mixed type, but the total concentration of this water is so low
that the relative proportions may not be meaningful.
The same water
after additional residence time in the rocks might dissolve relatively
much more sodium than other constituents, thereby acquiring the
20
Tippipah
Captain Jack
Oak
Tubb
Whiterock
Cane
Water from springs
Water from fractures in tunnels
(analysis number in parenthesis)
Crosscut
Shaft
Plotting scheme
and scale (in
equivalents per
million)
Water from granodiorite
Figure if.--Chemical diagrams representing water from springs and tunnels
in tuff, and water from granodiorite.
21
character of a typical "tuff" water.
The spring water is described
further in the section entitled, "Water from springs and tunnels."
Water from carbonate rockd
Some of the water from the carbonate rocks is of the calciummagnesium type, which' makes a semicircle in the north half of the pie
diagram, with almost nothing in the south half.
The amount of magnesium
in the water from test hole 90-67b is about three times the amount of
calcium, and indicates that the water-bearing rock is dolomite, or at
least is dolomitic.
This inference is confirmed by Houser and Poole
(1959> P« H) > wbo state that the composition of the rock penetrated
in the hole is "dolomite from the surface to about 5^0 feet and limy
dolomite from ^kO to 95! feet."
The magnesium in some other water
is but slightly greater than, or is approximately equal to, the calcium;
for example, well 88-66.
The calcium predominates in other water;
for example, well 67-68.
Not all the water from carbonate rocks is of calcium-magnesium
type.
Several are of mixed chemical type, among them the water from
wells 87-62, 79-69a, and 75-73.
The sodium in such water probably is
due to contact of the water with tuffaceous materials; that is, passage
of the water through tuff or through alluvium containing detrital
tuff.
The water may have entered carbonate rock and then have passed
through tuffaceous materials and back into carbonate rock; or it may have
entered tuffaceous materials first and then have moved into carbonate
rock.
22
Water from alluvium
The chemical character of water in alluvium depends to a considerable
degree on the kind of rock materials that make up the alluvium.
It
differs from place to place in accord with the character of the source
rocks from which the alluvial detritus is derived.
on the relation of alluvium to the bedrock aquifer.
It also may depend
Several situations
affecting the chemical character of ground water at and near the Nevada
Test Site are described below.
Water from alluvium containing detrital tuff is likely to resemble
water from tuff but may contain relatively more calcium and magnesium
than a typical "tuff" water.
The alluvium in Frenchman Flat, as repre-
sented by well 7l|--70b (Hood, 1961, p. Mf-48), contains detrital limestone, dolomite, quartzite, rhyolite, tuff, and argillite.
The water
from wells 7^~?0a anc* 7^'TOb ^ s a sodium-potassium type much like some
% the spring water that issues from tuff.
of
Both water types contain
a little calcium and magnesium, although the maximum is only 12 percent
of total cations.
In fact, the amount of calcium and magnesium in this
water is surprisingly low in view of the prominence of limestone and
dolomite in the descriptions of the well log.
By contrast, the water of well 83-68 seems to have more calcium
and magnesium than would be expected from the description of the strata
at the well.
The well penetrates only alluvium, which contains relatively
large percentages of various kinds of detrital tuff, together with somewhat smaller amounts of quartzite, chert, and argillite (Price and
Thordarson, 1961, p. 18-29).
Carbonate-rock detritus is insignificant,
although carbonate rocks are exposed both east and west of the well.
23
Yet, the calcium and magnesium in the water are enough to put the water
on the boundary between the sodium-potassium and mixed types.
Water from alluvium is usually chemically similar to the water
from the carbonate rocks if carbonate-rock detritus is abundant, as
in the case of well 65-73-
This well penetrates alluvium "consisting
principally of fine- to medium-grained dolomite and quartzite fragments
in a calcareous-silt matrix" (Moore, 19^2, p. 10).
The dolomite fragments
could have been derived from rock outcrops either north of the well
in the Spotted Range or south of it in the Spring Mountains.
The water
from the well is a calcium-magnesium water, with magnesium slightly
exceeding calcium; sodium, sulfate, and chloride are negligible.
The ground water in alluvium may not have any obvious relation
to the lithology of the alluvium in some special geologic situations.
Where water from bedrock aquifer is discharged into alluvium, the chemical
character of a water sample collected near the place of discharge may
be dominated by the influence of the bedrock aquifer; only with extended
residence in the alluvium will the water acquire a chemical character
compatible with its host.
Such a situation could easily lead to
uncertainty in interpretation of a chemical analysis, especially where
subsurface conditions are but partly understood, or the subsurface
discharge is not believed to occur.
For example, water from a well
ending in alluvium that taps water discharged into the alluvium from
a carbonate-rock aquifer, in a locality where the nearest exposed rock
is tuff, would seem anomalous.
2k
Water from granodiorite
The Climax stock, which is at the north end of Yucca Flat, consists
of granodiorite and quartz monzonite and probably contains water only
locally.
The water seems to occur where the rock is most fractured,
in more or less isolated bodies.
The water probably is replenished
from precipitation on the immediate area.
The fractures containing
the water are poorly connected, and its movement is restricted so
severely that each water body seems to have its own independent level
(Walker, 1962, p. 36).
It is doubtful that the water in the granite
moves away in significant quantities into the surrounding Paleozoic
rocks.
Samples from two closely spaced sites in the granodiorite stock,
taken from different depths below the land surface, proved to be calciummagnesium sulfate water (fig. k).
The sulfate content is notably high,
especially in comparison with the amount of sulfate in water from other
types of rock.
The water in adjacent rocks contains much less sulfate
indicating that not much water can be moving out of the stock.
This
inference is confirmed by the dissolved solids, which in both samples
is much greater than in most samples from other sources in the vicinity.
The nearest approach in terms of dissolved solids is the water from
well 89-68.
This well is about 2 miles southeast of the stock.
It
penetrates more than lj-,200 feet of quartzite, argillite, quartzitic
siltstone, and dolomite, of Paleozoic age, and the water from it is of
mixed chemical type.
The dissolved-solids content of the water is only
lj-30 ppm, and the sulfate content is about 60 ppm probably too low for
any significant contributions of water to have come from the granodiorite.
25
UNUSUAL WATER TYPES
Some waters from the Nevada Test Site and vicinity seem to be
anomalous..Possible explanations for some of them are suggested in the
following paragraphs.
Water of mixed type from tuff
The water from well 81-67 (Yucca Flat) is of mixed type, not at all
the sodium-potassium water to be expected from a well ending in tuff.
Calcium and magnesium are nearly equal, and together they exceed slightly
the sum of sodium plus potassium.
The calcium and magnesium may be
traceable to a buried north-south ridge of Paleozoic rock situated a few
miles west of the well.
This rock in a test hole about 3 miles north-
west of well 81-67 is limestone and shale or siltstone (Moore, 1962,
p. 38-39), and it begins only 72 feet below the land surface.
Water
coming to the well from the west, therefore, may have had a longer
history in the carbonate rock than it had in tuff.
The mixed chemical
character may be due to mixing in or near the well of calcium-magnesium
water from the west with sodium-potassium water coming from other
directions.
Water high in sulfate
The water from well 73-61 is exceptional because in it the sulfate
is five times the bicarbonate, whereas in most water of the Test Site
the sulfate is monor or negligible.
tuff.
The aquifer tapped by the well is
The nearest well showing a substantial amount of sulfate is
number 73-66, which is about 8 miles to the east.
There the sulfate was
in water from carbonate rock and was somewhat less than the bicarbonate.
The water at both wells may have been influenced by the same factors,
although not equally.
26
The dominance of sulfate in the water at well 73-61 and the relative
abundance of it in the water at well 73-66 may be traceable to the geologic
process that caused extensive hydrothermal alteration of the volcanic
rocks, and less extensively the Paleozoic carbonate rocks, in the hills
bordering Jackass Flats on the north, 5 miles from well 73-61.
Silici-
fication, alunitization, and kaolinitization were intense enough to destroy
much of the original texture of the volcanic rocks (E.J. McKay, written
communication, 1962) .
and potassium.
Alunite is the basic hydrous sulfate of aluminum
Therefore, the ground water in this area may be expected
to contain substantial amounts of sulfate.
The sulfate in the water from
the carbonate rocks at well 73-66 may be due to water that has come from
the hydrothermally altered area.
Water high in sulfate and in dissolved solids
The water from well 68-69, which was drilled in Mercury Valley in
search of water for Camp Desert Rock, contains more than 5,000 ppm of
dissolved solids (table 1).
This is nearly twice as much as in the next
most mineralized water considered in this report, which is from a well
in the southern part of the Amargosa Desert (Well 61-53), and six times
as much as in the most mineralized water within the Test Site (Well 73-61) .
A chemical diagram for this water is not shown on figure 1 because if
drawn to the same scale as the other diagrams it would obscure too many
significant features of the map.
The water is a sodium sulfate type-
1,291 ppm of sodium (72 percent of total cations) and 3,599 ppm of sulfate
(94 percent of total anions).
The water-bearing strata at the well, as
indicated by a broadly generalized driller's log (Moore, 1962, p. 26),
may be interpreted either as alluvium or rhyolite, or both.
The log offers
27
Table 1. Analyses of water from wells 66-69 and 68-69, in parts
per million and equivalents per million
^fell 66-69
(Army 6A)
Parts per
million
Equivalents
per million
bWell 68-69
(Camp Desert Rock)
Parts per
million
Silica (SiOa )
Equivalents
per million
22.6
Calcium (Ca)
24
1.20
281
14.02
Magnesium (Mg)
16
1.32
90
7.40
222
9.66
1,291
56.16
11
.28
486
7.97
98
1.61
0
.00
tr
Sulfate (S04 )
169
3.52
3,599
74.93
Chloride (Cl)
23
.65
98
2.76
Sodium (Na)
Potassium (K)
Bicarbonate (HCO.J
o
Carbonate (C03 )
Fluoride (F)
Nitrate (N03 )
"Phosphate (P04 )
Dissolved solids
Residue at 180° C.
Sum
Hardness as CaC03
Total
Non-carbonate
Specific conductance
(Micromhos at 25° C.)
pH
.8
.04
4.1
.07
2.7
703
71 fl
5,416
1 O£
1,073
o
......
1,130
8 n
______
Analysis by U.S. Geological Survey, Denver, Colo.
Analysis by Smith Emery Co., Los Angeles, Calif.
8.1
28
no helpful explanation for the mineralization of the water.
The water
is so different from other waters of the region that unknown local
factors must be the cause.
Possibly the water in the alluvium at Camp
Desert Rock is stagnant and has become highly mineralized as a result
of long contact with rocks that include a source of sulfate material
not recognized at the surface.
Evaporite deposits included in the
alluvium might be such a source.
Concentration of the water by
evaporation might have occurred under topographic and climatic conditions
of the geologic past, but is unlikely under present conditions.
The
static water level at Camp Desert Rock, about 975 feet below the lafcd
surface, is too deep for evaporation.
If the water entering the Mercury
basin was a bicarbonate type, as is most of the water of the region, a
mechanism for minimizing the bicarbonate and increasing the sulfate must
have operated.
Another inference based on the unusual character of the water
from well 68-69 is that the confining layer under the zone of saturation
provides a relatively tight seal.
The mineralized water seems not to
appear in wells tapping other aquifers.
The well is less than 3 miles
"upstream" from well 67-68, which taps carbonate rock and has water
containing only 330 ppm dissolved solids and 38 ppm sodium (28 percent
of total cations) .
No more than a trickle of the mineralized water
can be reaching the carbonate-rock aquifer at well 67-68.
High sodium in calcium-magnesium area
Well 66-69, known also as Army well 6A and as the Riess well (from
the name of the Army 1 s consultant), yielded a sodium-potassium water
29
from a part of the area where other water, so far as they are
represented by analyses, is of the calcium-magnesium type.
The
dissolved-solids content of the water was relatively (but not
excessively) high, about 700 ppm; sodium was 222 ppm (78 percent of
total cations), bicarbonate was 486 ppm (66 percent of total anions),
and sulfate was 169 ppm (table 1) .
The log of the well (Moore, 1962,
p. 17-19) shows the water-bearing strata to be quartzite, in wfytch
soluable sodium is improbable.
The water sampled does not represent
the formation water, perhaps because it was contaminated by the
cement used in the well during drilling.
J. D. Hem (written communi-
cation, 1963) pointed out that the bicarbonate content is high
relative to the pH, making a system in which calcium probably would be
precipitated as calcium carbonate.
If a water having the characteristics
shown by the analysis were to be mixed with a calcium carbonate type
(possibly formation water), the final solution would contain relatively
small amounts of calcium.
Owing to doubt as to the validity of the
sample, the analysis is not plotted on figure 1 nor considered further.
It is mentioned chiefly because the history of the well and the results
obtained from it are well known in southern Nevada.
Unlike water from adjacent wells
Wells 79-69a and 79-69b are only about 100 feet apart at the land
surface, but the analyses of the water samples from them were not alike.
Both wells (hereafter for convenience in these paragraphs simply wells
"a" and "b") draw water in substantial quantities solely from fractured
carbonate rocks, (Garber and Thordarson, 1962, p. 19 and 27), but the
30
specific capacity -' of well "a" is much greater than that of well "b. 11
Both wells were drilled to a depth of about 1,700 feet, but well "b"
after reaming and casing is effectively only 1,650 feet deep.
The water
samples seem to represent fairly the formation water from each well, for
the following reasons.
Three water samples from well "a" were collected over an 8-month
period during which the well was pumped regularly at 200 gallons per
minute, or more.
The analyses show only relatively small variations in
the amounts of the principal anions and cations (appendix A).
The
relative constancy in chemical composition therefore suggests that water
was being drawn from a large reservoir.
Only one sample was collected from well "b'/1 but it was taken after
about 6,000,000 gallons of water had been pumped out (R. A. Young, oral
communication, 1963).
Averages of the principal ions for the three samples from well "a"
may be compared in table 2 with the corresponding ions in one sample from
well "b."
1.
The principal dissimilarities in the waters follow:
The water from well "b" was a sodium-potassium type having only
a moderate proportion of calcium and magnesium, but the water from well
"a" was of mixed chemical type, in which the calcium and magnesium is
nearly equal to the sodium and potassium.
2.
The water from "b" had only 0.75 as much dissolved solids as
that from "a."
Specific capacity is the discharge, in gallons per minute,
divided by the drawdown, in feet.
31
3.
The calcium in the water of well "a" was 1.84 times as much
as the magnesium, but in the water of well "b" the relation was reversed.
In "b" the magnesium was 2.77 times as much as the calcium; only at well
90-67b, among wells at the Test Site, does the magnesium exceed the
calcium by a greater amount, and there it is 3.1 times the calcium.
4.
The calcium was only about one-fifth as much in the water from
"b" as in the water from "a."
The greatest single difference between the two is in the calcium.
The other ions in table 2 differ only by 5 to 15 percent, but the
calcium in water from "a" is 4.5 times that in water from Mb. M
Water
similar to that from "b" could be made by removing about 3 epm of calcium
carbonate from the water of well "a."
This simple relation, together
with the fact that the pH of the water from "a" was about 7, whereas that
for "brl was over 8, led J. D. Hem (written communication, 1963)to suggest
that calcium carbonate was being precipitated near well "b," probably
in the rock openings adjacent to the well, and that the precipitates are
in part responsible for the relatively low specific capacity of the well.
The magnesium would not necessarily be precipitated along with the
calcium.
32
Table 2. Principal ions in water from wells 79-69a and 79-69b,
in equivalents per million
Well 79-69a
(average of three
analyses)
Well 79-69b
(one analysis)
Calcium (Ca)
3.72
0.83
Magnesium (Mg)
2.02
2.30
Sodium (Na)
5.80
5.48
.34
.38
9.36
6.33
.00
.20
Sulfate (S04 )
1.45
1.27
Chloride (Cl)
.86
.99
Potassium (K)
Bicarbonate (HCO,)
w
Carbonate (CO.)
3
Dissolved solids (residue on
evaporation at 180° C., in ppm)
644
482
Hem's suggestion led to the collection of new-water samples from
both wells, and to a series of field measurements of the conductivity
of the water for an hour preceding the sampling after an initial conductivity of 880 micromhos at well "b," the conductivities at the two
wells were similar within the narrow range of 980 to 1,000 micromhomos.
\
The calcium and bicarbonate were similar to the original water samples
from well "a" (table 3).
Thus, the difference between the waters from
the two wells seemed to have disappeared.
This result led R.C. Scott
(oral communication, 1963) to suggest that the water of both wells is
and was the same chemically, and that the low calcium content of the
33
first water sample from well "b" was due to precipitation of calcium
bicarbonate while the sample was in transit or in storage.
Whether.' the foregoing chemical anomalies are due to precipitation
in fractures of the aquifer or in the sample bottle, or to some other
cause, remains a matter for speculation.
It is worth mention that the
first sample from well "b" was collected nearly 6 months after the
collection of the last sample from well "a" that was completely analyzed
and that the last two, partially analyzed samples were collected after
both pumps had been shut down for an unreported period of time.
Obviously
the conditions in the aquifer were not the same on any two sampling dates,
Just as obviously, the conditions that prevailed at collection of the
first samples cannot be duplicated, if only because a large quantity
of water then in the aquifer has since been pumped out.
The nearest
approach to a solution to this problem might consist of sampling for
chemical analysis the discharge of both wells when both have been pumped
continuously for a protracted time.
34
Table 3.--Calcium and bicarbonate in water from wells 79-69a and
79-69b
Calcium (Ca)
(epm)
Bicarbonate (HC03 )
(epm)
Sept. 1, 1961
3.69
9.46
Jan. 19, 1962
3.49
9.18
Apr. 25, 1962
3.99
9.44
3.72
9.36
3.99
9.31
Oct. 10, 1962
.83
6.33
Mar. 19, 1963
3.94
9.34
Well a
Averages
Mar. 19, 1963
Well b
WATER FROM SPRINGS AND FROM TUNNELS
Selected chemical analyses of waters from springs and tunnels are
tabulated in appendix B and are illustrated by chemical diagrams in
figure 4.
The most recent analysis is given for each spring.
Additional
chemical analyses of water from springs and tunnels are given in reports
by Moore (1961, table 5A) and Clebsch and Barker (1960, table 2A) .
Eight springs are present within the boundaries of the Nevada Test
Site, and all discharge water from perched zones of saturation in tuff
and rhyolite.
Their discharge ranges from less than 1 to_3 gallons per
minute (Moore, 1961, p. 17).
The water-bearing bed of six of them is
zeolitized tuff in the lower member of the Indian Trail Formation.
The
water-bearing rocks of Cane and Topopah Springs are calcareous tuff and
rhyolite, respectively. Topopah, Tippipah, Rainier, Captain Jack, and
35
Whiterock Springs yield water of the sodium-potassium type, closely
resembling the water from wells in tuff in Frenchman and Yucca Flats.
The sodium and potassium content of these waters ranges from 64 to 93
percent of total cations, and bicarbonate ranges from 64 to 79 percent
of total anions.
Dine, Oak, and Tubb Springs yield water of the mixed chemical type.
The sodium and potassium content (44 to 57 percent of total cations) is
about equal to the calcium and magnesium content (43 to 56 percent of
total cations).
The source of the calcium and magnesium at Oak and Tuff
Springs is not apparent.
The calcium content (38 percent of total cations)
of the water of Cane Spring apparently is due to the contact of the water
with dacitic tuff, which has a higher calcium content than the rhyolitic
tuff.
The dissolved-solids content of the spring water of the Test Site
is relatively low, ranging from 123 to 362 ppm (appendix B), and the
average (220 ppm) is about 65 ppm lower than the water in wells that
tap tuff or tuffaceous alluvium in Emigrant Valley, and Yucca Flat, and
165 ppm lower than in Frenchman Flat.
In contrast the dissolved-solids
content of two springs in the Amargosa Desert, which are fed from the
main zone of saturation, is substantially higher 468 and 500 ppm.
The tunnel samples were collected from seeps discharging from
fractures in the tunnels in Rainier Mesa.
They represent water from
perched zones of saturation in zeolitized tuff, which are replenished
by precipitation on the mesa.
Almost all waters from the tunnels are
of the sodium-potassium type.
The sodium and potassium ions (65 to 98
*
percent of total cations) predominate in 23 to 26 samples.
In the
36
remaining samples the calcium and magnesium content is about equal to
that of sodium and potassium.
The high calcium content of these three
water samples may have resulted from contact with calcareous tuff.
source of the magnesium is apparent.
No
The chemical composition and the
dissolved-solids content (91 to 334 ppm) of the tunnel waters is similar
to that of the springs, if the calculated dissolved solids is accepted
instead of residue on evaporation in analyses where the residue is much
greater than the calculated solids (Appendix B; Clebsch and Barker, 1960,
p. 15-18).
In these analyses the residue may have contained suspended
matter.
CHEMICAL CHARACTER OF GROUND WATER BY AREAS
The chemical character of ground water in Indian Spring Valley,
Yucca and Frenchman Flats, Jackass Flats, and the Amargosa Desert is
shown by parallelogram diagrams (fig. 5) and on maps by pie diagrams
(figs. 1 and 6).
The chemical composition of the water of these areas,
in percentage of chemical equivalents of cations and anions, is summarized
in tables 4 to 7.
Indian Spring Valley
The ground water from Indian Spring Valley is of the calciummagnesium type.
The calcium and magnesium range from 84 to 94 percent
of total cations, and the bicarbonate ranges from 84 to 89 percent of
total anions (table 4).
The calcium and magnesium are nearly equal.
Sodium and potassium are negligible and by their near absence suggest
that the water has had little or no contact with tuffaceous rock.
49
50
Alluvium
Carbonate
rock
Test
well 4
Cactus
Spring
Indian
Spring
66-75
66-77
66-79
Carbonate
rock
Alluvium
Army 3
65-76
46
40
45
Alluvium
Army 2
44
45
38
50
48
Calcium Magne(Ca)
slum
(Mg)
65-73
Aquifer
Name
Well or
spring
number
6
6
16
9
6
Sodium
(Na)
Percent of total cations
0
0
0
1
1
Potasslum
(K)
88
89
84
88
87
Bicarbonate
+ carbonate
(HC03 + C03 )
4
5
6
8
7
5
5
Chloride +
fluoride +
nitrate
(C1+F+ND3 )
9
7
8
Sulfate
(S04 )
Percent of total anions
Table 4. Composition in percentages of chemical equivalents of cations and anions of water
from Indian Spring Valley
00
39
This seems to be true notwithstanding the fact that 450 feet of tuff
/
i
was penetrated below the alluvium in well 65-76 (Moore, 1962, p. 1416).
The tuff has a calcareous matrix but has little or no zeolitic
material; it is more likely to yield calcium than sodium, and probably
would yield water much less freely than the alluvium.
The principal
\
aquifer is probably the alluvium, in which detrital carbonate rock is
abundant, and the water sample consisted principally, if not entirely,
of water from the alluvium.
The principal aquifers in Indian Spring Valley are dolomite and
alluvium containing detrital dolomite.
The chemical composition of the
aquifers explains the predominance of calcium and magnesium in the water.
Frenchman and Yucca Flats
Ground water in Frenchman and Yucca Flats falls into all three of
the principal chemical types discussed in this report.
The sodium-potassium water is from wells in tuff or wells in
alluvium containing detrital tuff.
The sodium-potassium content of
six wells is high, ranging from 87 to 98 percent (table 5); at one well
(83-68) it is 60 percent, barely enough so that the water may be classed
as of the sodium-potassium type.
The high sodium content of these waters
is due in part to the solution of sodium minerals in the volcanic tuff
and in part to ion exchange.
The alluvium and tuff in Yucca and French-
man Flats contain a large amount of zeolite and montmorillonite clay,
both of which are ion-exchange minerals.
As ground water containing
calcium and magnesium moves through these materials, calcium and
magnesium are replaced by sodium.
3
32
32
25
Alluvium
5C
Test
Carbonate
well 3 rock
Test
Carbonate
well C rock
Well 3
Test
Alluvium
well A
Test
Tuff
hole 7
Test
Tuff
well F
75-73
79-69
81-67
83-68
84-68
84-69
Tuff
2
1
27
9
74-70b
Alluvium
5B
1
0
1
13
27
14
21
1
4
1
Calcium Magne(Ca)
s ium
(Mg)
74-70a
Tuff
Aquifer
5A
Name
73-70
Well
number
82
92
5
2
55
96
96
84
80
5
2
80
3
51
43
69
2
45
59
84
5
82
85
Bicarbonate
+ carbonate
(HC03 4COa )
9
1
11
11
14
22
9
24
8
Sulfate
(S04 )
7
7
7
9
6
9
7
17
7
Chloride +
fluoride +
nitrate
(Cl+F+NO,)
3
Percent of total anions
2
2
96
94
Potass ium
(K)
Sodium
(Na)
Percent of total cations
Table 5.--Composition in percentages of chemical equivalents of cations and anions of water
from Frenchman and Yucca Flats
40
14
66
29
27
21
Carbonate
Test
well 2 rock
Carbonate
rock
UE15d
ME -3
88-66
89-68
90~67b
Carbonate
rock
26
0
29
do
6
11
54
27
43
93
81
87
2
80
70
73
9
14
12
21
13
4
5
8
9
14
Percent of total anions
Chloride +
Bicarbonate
Sulfate
fluoride +
4- carbonate
(S04 )
nitrate
(HC03 -HI03 )
(C1+F+NOJ
o
5
4
2
1
Percent of total cations
Calcium MagneSodium
Potas(Ca)
sium
( Na)
s ium
(Mg)
(K)
Carbonate
rock
Do
Test
Tuff
well 1
87-62
Aquifer
Name
Well
number
Table 5.--Composition in percentages of chemical equivalents of cations and anions of water
from Frenchman and Yucca Flats Continued
42
The calcium-magnesium water is present in wells 88-66 and 90-67b,
both of which are in dolomite in the northern part of Yucca Flat.
Calcium
and magnesium total 69 and 87 percent of the total cations and bicarbonate
is 80 and 87 percent of total anions, respectively.
The water in these
wells differs from others in Frenchman and Yucca Flats, apparently because
it has been in contact mainly with carbonate rock and little or no mixing
with tuff water has taken place.
Their chemical composition closely
resembles the water of Indian Spring Valley.
The mixed chemical type of water is principally from wells in
carbonate rock, but one well in tuff (Well 81-67) also has water of mixed
chemical character.
(See section on unusual water types).
Two water
samples from carbonate aquifers have sodium and potassium exceeding
f
calcium and magnesium. None of these water samples show a significant
predominance of either sodium plus potassium or calcium plus magnesium.
The content of sodium and potassium does not exceed 59 percent of total
anions, and the content of calcium and magnesium does not exceed 55
percent.
Jackass Flats (including Rock Valley)
Ground water in Jackass Flats and Rock Valley falls into three
chemical types, one of which is a sodium-calcium sulfate type unusual in
the region.
The others are the sodium-potassium and calcium-magnesium
types that seem to be normal to the area.
The sodium-potassium water is from wells 73-58, 73-66, and 74-58,
all of which tap tuff.
Well 73-66 taps carbonate rock, also; and there-
fore is discussed in some detail in the following paragraph.
Although
sodium is the predominant cation (62 to 83 percent) in the sodiumpotassium water of the Jackass Flats-Rock Valley area, the proportion of
43
calcium also is substantial, ranging from 13 to 25 percent (table 6).
Except for this higher calcium content, these waters are similar to the
waters from wells in tuffaceous materials in Frenchman and Yucca Flats.
The calcium-magnesium water is from the carbonate aquifer in well
73-66, Rock Valley.
This well penetrated 3,137 feet of tuff and 263
feet of underlying dolomite, and water samples from both the tuff and
the dolomite were analyzed.
The water from the tuff is perched and,
as noted above is a sodium-potassium type; it contains only 15 percent
calcium and magnesium.
The water from the dolomite is of the calcium-
magnesium type, with calcium and magnesium making up 66 percent of total
cations four times as much as in the water from the tuff.
The sulfate
content of the water from the dolomite (43 percent of total anions) is
markedly higher than in the water of the tuff (14 percent), and is, in
fact, abnormally high for the region.
The sodium-calcium sulfate water is from the tuff aquifer in well
73-61.
The sodium is 53 percent and the calcium is 35 percent of total
cations.
high.
The sulfate is 80 percent of total anions and is unusually
By contrast the sulfate content in waters from two wells only
6 miles to the west is less than 17 percent.
The only other water
samples from the Nevada Test Site that had sulfate as the predominant
anion are two from the granodiorite at the north end of Yucca Flat.
Substantial proportions of sulfate are present in some of the water from
localities outside the Test Site, notably the Amargosa Desert and Mercury
Valley, but these probably are not related to those of the Jackass FlatsRock Valley area.
Tbe significance of the sulfate in wells 73-61 and 73-
66 is discussed further in the section on "Water high in sulfate. 11
74-58
Test
well 6
do-
13
Tuff
Test
well F
73-66
Do
35
Tuff
J-ll
73-61
28
7
38
22
Tuff
2
9
8
Carbonate
rock
25
Tuff
J-12
73-58
Calcium Magnesium
(Ca)
(Mg)
Aquifer
Name
Well
number
65
31
83
53
62
Sodium
(Na)
Percent of total cations
6
3
2
3
5
Potassium
(K)
68
52
64
14
70
Bicarbonate
+ carbonate
(HC03 +C03 )
17
43
14
80
15
Sulfate
(S04 )
15
5
22
6
15
Chloride +
fluoride +
nitrate
(Cl+F+NCL)
o
Percent of total anions
Table 6.--Composition in percentages of chemical equivalents of cations and anions of water
from Jackass Flats (including Rock Valley)
45
Amargosa Desert
The Amargosa Desert has been shown by Eakin and others (1963, p. 2024) to be the most probable place for discharge of ground water moving
out of the Nevada Test Site.
Their conclusions are based on the hydraulic
potential across the region, the relation of discharge to recharge in
different basins, and the chemical character of the water.
They have
shown further that probably no more than 7£ percent of the discharge
known to take place in the Amargosa Desert can be derived from recharge
within the Nevada Test Site.
Their inferences that are based on the
chemical character of the ground water are amplified in the following
paragraphs, which relate to the southwestern part of the desert beginning
near Lathrop Wells (fig. 6) .
Most of the water that has been sampled in the Amargosa Desert,cis.
from alluvial aquifers, but may not be native to them.
Some water may
have been discharged into them from underlying carbonate-rock or other
aquifers.
More than one hydraulic system seems to be represented, but
distinctions cannot be made on the basis of data now available; therefore,
only the gross features of the ground-water chemistry can be presented
here.
Figure 6 and table 7 show that most of the water is the mixed
chemical type.
Those of the eastern side of the figure have somewhat
more calcium and magnesium than sodium and potassium.
The sodium and
potassium increase westward, and they predominate in five water samples
along the western margin of the desert.
As sodium and potassium increase, the calcium and magnesium decrease,
and this (fig. 1
suggests that the eastern waters are in part derived
54
6420246
i I i I*i i i
52
56
Death \\Valley
Junction
56-58
5
**+
62
Test Site boundary
E600.000
Lathrop Wells
58
66
I ^vV ^
64
\
V
68
Figure 6.--MAP OF THE SOUTHWESTERN PART OF THE AMARGOSA DESERT SHOWING CHEMISTRY OF GROUND WATER.
POTASSIUM TYPE, BLACK; MIXED TYPE, RULED.
AQUIFERS: A, ALLUVIUM;
L, LAKE BED
SCALE IN MILES
058-61
PLOTTING SCHEME AND SCALE
(IN EQUIVALENTS PER
MILLION)
E 500,000
SODIUM-
00,000
N 500,000
52
54
56
58
N 600,000
62
64
66
68
M "7
E700.000
Alluvium
16
23
28
29
64-57
64-64
Alluvium
10
28
64-54
White
well
29
27
63-64a
23
34
62-60
44
52
58
41
40
94
2
1
54
40
52
56
95
14
22
18
19
2
61-59
Ray Van Alluvium
Horn well
27
Alluvium
....
59-62
61-53
35
Alluvium
Big
Spring
59-61
27
23
deposits
58-61
Aquifer
1
Name
56-58
Well
or spring
number
4
4
4
3
3
3
5
3
3
2
2
Percent of total cations
Calcium MagneSodium
Potasslum
(Ca)
sium
(Na)
(Mg)
(K)
34
15
53
82
14
20
70
69
10
22
68
3
13
17
10
8
20
72
11
10
9
10
18
Chloride +
fluorlde +
nitrate
(C1+F+NOJ
«3
21
23
28
29
31
Sulfate
(S04 )
68
67
63
61
51
Bicarbonate
+ carbonate
(HC03 -KJ03 )
Percent of total anions
Table 7. Composition in percentage of chemical equivalents of cations and anions of water
from the Amargosa Desert
CO
ft
AQ..S7
eo
66-58
ff
66-56
CO
fe
Well
or spring
number
Alluvium
Alluvium
Alluvium
.
.
-.
Alluvium
.
,
Aquifer
Name
28
36
28
13
17
7
6
2
4
L
^
5
3
5
51
52
63
80
?n
54
62
46
73
20
34
29
35
16
in
12
9
19
11
Percent of total cations
Percent of total anions
Calcium MagneSodium
Potas- Bicarbonate Sulfate
Chloride +
(Na)
sium + carbonate
fluoride +
(Ca)
sium
(S04 )
(Mg)
nitrate
(K)
(HC03 +C03 )
(C1+F+N03 )
Table 7.--Composition in percentage of chemical equivalents of cations and anions of water
from the Amargosa Desert Continued.
Go
49
from recharge in the Spring Mountains, which lie to the east and contain
carbonate-rock formations.
The water received as precipitation on the
west slope of the mountains moves westward into the valley as a calciummagnesium type.
In this valley it mixes with sodium-potassium type
arriving from another direction, or it picks up sodium in the alluvium
by solution or ion exchange.
The farther west it moves, the larger the
proportion of sodium and potassium becomes.
The relation of recharge to water chemistry that is suggested in
the preceding paragraph is seen also in Pahrump Valley, which is flanked
on the east by the Spring Mountains.
Pahrump Valley is, in fact, closer
to the Spring Mountains recharge area than is the Amargosa Desert, and
the ground water there is of the calcium-magnesium type and nearly free
of sodium and potassium (Eakin and others, fig. 3) .
The mixed character of the waters in the eastern and central part of
the area shown on figures 6 and 7 may be due in part, also, to influx of
water from the carbonate rocks of the Nevada Test Site, which has been
shown elsewhere in this report to be of mixed character.
Water from the
western part of Indian Spring Valley also might move into the Amargosa
Desert, acquiring a mixed character en route.
The five high-sodium water samples are aligned northwest-southeast
along the western side of the desert, and the southeasternmost has the
highest dissolved solids.
Their alingment coincides with the general
direction of the surface drainage, and probably also with the direction of
movement of the ground water.
steady progression.
The dissolved solids do not increase in a
The second and third water samples represented in
figure 6 (beginning from the northwest) are less mineralized than the
Figure 7.--Map of the southwestern part of the Amargosa Desert showing the distribution of calcium plus magnesium
in ground waters, expressed as percentage of total cations. Area covered and water sources are the same as
in figure 6.
Scale in miles
Line showing equal per
centage of calcium
plus magnesium (percentage of total
cations)
01 25^.5
51
first, but the overall increase is apparent.
This increase may be due
in substantial part to concentration by evapotranspiration at places of
natural discharge, which are the places where samples were collected.
However, the increase may also be due in part to solution of additional
mineral matter during underground travel and together with the alingment
suggests movement of sodium-potassium water from the northwest into the
area.
The increase in dissolved solids cannot be denied, but the
alignment may be somewhat deceptive because the distinction between
mixed types and high-sodium types is necessarily arbitrary.
The more
western of the mixed types have as much as 58 percent in sodium and
potassium; the high-sodium water has only somewhat more than 60 percent.
This arbitrary distinction may account for the fact that the water from
well 61-53 breaks the alingment of high-sodium samples.
Nevertheless,
the percentage of sodium plus potassium is unquestionably higher along
the western side of the area, and a general movement of sodium-potassium
waters from the northwest seems to be a strong probability.
The high-sodium water shows a southeastward decrease in calcium and
magnesium that may be significant.
At wells 66-52 and 64-54 the calcium
and magnesium total 34 and 38 percent, respectively, but at wells 61-59
and 56-58 they are only 3 percent.
Wells 65-53 and 61-53 do not fit the
progression, and, hence, may be presumed to be subject to other influences
If ground-water movement is from northwest to southeast, the decrease in
calcium and magnesium may be due to ion exchange.
52
W&TER MOVEMENTS INFERRED FROM DISSOLVED SOLIDS
The amount of dissolved solids in ground water depends on several
variables, ranging from the quantity of carbon dioxide dissolved in the
water to the kinds and solubility of the rocks and minerals, and it may
suggest the direction in which the water has moved.
The variables are
such that small differences in the dissolved solids are likely to be
meaningless, or at least not interpretable, but some of the larger
differences seem to have meaning.
For example, the waters from springs
and those from tunnels in Rainier Mesa (Clebsch and Barker, 1960, table
2A; Moore, 1961, table 5a; this report, appendix B) seem to have had only
relatively short contact with the rocks.
Some but by no means all the spring waters are low in dissolved
solids (table 8).
The springs are fed by perched zones of saturation in
volcanic rocks, chiefly tuff.
These zones of saturation probably are
relatively small in areal extent, and the recharge to them is derived
from the precipitation on nearby areas.
The route of ground-water travel
and the residence time therefore may be presumed to be short.
Seasonal variations in dissolved solids at Whiterock Spring are
suggested by a series of five analyses (table 9).
The analyses are not
spaced closely enough nor regularly enough to show seasonal changes
accurately.
Rather, they show a wide range that is presumed to be
seasonal because the static water level in a test hole adjacent too the
spring, as recorded by a recording gage, fluctuates widely in response
to precipitation in the immediate vicinity (Winograd, oral communication,
1963) .
The range in dissolved solids as shown by residue on evaporation
was from 184 to 362 ppm, or about 1 to 2.
If the calculated dissolved
53
solids is considered instead, on the basis that some of the residues were
erroneous because of turbidity of samples, the range is from 149 to 243
s
ppm, or about 1 to 1.6.
In either case, the variations in dissolved solids
suggest that some of the paths between the places of recharge and the
spring are relatively short and direct.
Table 8. Dissolved solids in spring water,
in parts per million
Nevada Test Site,
Number
Name of spring
88-64
Captain Jack
178
90-67
Oak
180
90-68
Tubb
185
83-63
Tippipah
159 - 194
79-61
Topopah
123 - 210
88-63
Rainier
250
74-66
Cane
288
89*65
Dissolved solids
184 - 362
Whiterock
Table 9. Variations in dissolved solids at Whiterock Spring,
Nevada Test Site, in parts per million
Date
Sept. 18, 1957
Mar. 21, 1958
Dissolved solids
CalcuRes. on
evap.
lated
184
184
265
243
Date
May 19, 1959
Dissolved solids
CalcuRes. on
lated
evap.
208
168
Jan. 29, 1960
352
149
Nov. 10, 1960
362
184
54
The water samples from fractures intersected in the tunnels in
Rainier Mesa are similar in dissolved-solids content to the spring water.
The total solids in 25 samples range from 91 to 334 ppm (appendix 3;
Clebsch and Barker, I960, p. 15-16), but the average is near the lower
end of the range:
176 ppm.
was between 100 to 200 ppm.
The dissolved solids in 18 of these samples
The sum of dissolved solids, rather than the
residue on evaporation, is evaluated for seven of these samples because
filtering failed to remove all the turbidity.
The residue on evaporation
is so much greater than the sum that suspended matter probably was
included in the residue.
The "tunnel" water, like the spring water, passed mainly or solely
through volcanic rock.
They were from a perched zone, or zones, of
saturation, or from fractures.
The samples may be presumed to have been
\
collected at points not far from the place or places of recharge, not
only because of their low content of dissolved solids but also because
i
of geologic/and topographic relations.
may not be far away.
The source of recharge, therefore,
This view is confirmed by the tritium analysis of
one sample of water from a tunnel, which indicates a residence time
underground of more than 0.8 year and less than 6 years (Clebsch, 1961,
p. C-124).
The water from wells and test holes that penetrate the regional
zone of saturation generally is more mineralized than the spring and
"tunnel" water, yet few of them contain more than 500 ppm, the desirable
limit recommended by the U.S. Public Health Service (1962) for dissolved
solids in water to be used for human consumption.
A few of the water
samples from the Nevada Test Site are very low in dissolved solids.
The
55
water from the Paleozoic carbonate rock in well 87-62, in the depth
interval from 3,700 to 4,206 feet, contains only 220 ppm dissolved
solids.
It compares favorably with the water from the uppermost perched
aquifer in tuff in the same well (412 to 560 feet), which contains 240
ppm.
The low dissolved-solids content of the water from the tuff
suggests that the site of recharge to the tuff is near.
The ground water in Indian Spring Valley is notably low in
dissolved solids.
The three analyses for the valley that are represented
on figure 1 range from 205 to 225 ppm in dissolved solids (wells 65-73, ',
65-76, and 66-75).
Two others that are from sources a few miles beyond
the east boundary of figure 1 contain 205 and 225 ppm, respectively
(weH 66-77 and spring 66-79) .
All are calcium-magnesium types, from
carbonate rocks or from alluvium presumed to contain detritus of such
rocks.
By contrast, the nearest well to the west that taps a carbonate
aquifer has half again as much dissolved mineral matter (well 67-68, in
Mercury Valley, 330 ppm) ; and the nearest well to the north has about
twice as much (well 75-73, in Frenchman Flat, 444 ppm) .
The only water
from carbonate rocks that is comparable in dissolved solids to Indian
Spring Valley is from well 87-62, which is discussed above, and well
88-66 (236 ppm).
If the amount of dissolved solids is meaningful, the
water of Indian Spring Valley might be moving westward into Mercury
Valley or northward into Frenchman Flat, but a reverse movement in the
opposite direction is unlikely.
If the water movement is westward or northward from Indian Spring
Valley, the proportion of calcium and magnesium should decrease in the
direction of movement and it does.
Whereas the calcium and magnesium
56
average 92 percent of total cations in the waters of Indian Spring
Valley, they are but 70 percent at well 67U £8 (Mercury Valley) and 53
percent at well 75-73 (Frenchman Flat).
Consideration of the dissolved solids in water from tuff and
tuffaceous alluvium suggests that recharge to these aquifers in the
Emigrant, Yucca, and Frenchman basins is local in origin; and, further,
that direct movement of water between basins through these aquifers
is unlikely.
The waters from three wells in Emigrant Valley that tap
tuff or tuffaceous alluvium are low in dissolved solids, averaging about
285 ppm.
This average is 70 ppm higher than the average for eight
springs from perched aquifers in tuff actually, 100 ppm or more higher
than the dissolved solids in five of the eight.
The average is also
about 100 ppm higher than the average for 25 water samples from tunnels
in Rainier Mesa.
These comparisons of average dissolved solids suggest
that the three water samples from Emigrant Valley have traveled somewhat farther, or have been somewhat longer underground, than the spring
and "tunnel" water.
The Emigrant Valley water and the water from three wells tapping
tuff and tuffaceous alluvium in Yucca Flat (wells 83-68, 84-68, and
84-69) averages about the same in dissolved solids.
The Yucca Flat
water, therefore, probably has not moved underground from Emigrant
Valley.
If they had done so, they probably should contain.more dissolved
mineral matter than the Emigrant Valley water types.
Omitted from con-
sideration here is the water of Yucca Flat well 81-67, which is of mixed
chemical type tnoughtft:comes from tuff, and is therefore discussed in
the section on "Unusual water types'."'
57
The average dissolved solids for the waters from three wells in
Frenchman Flat that tap tuff or tuffaceous alluvium is about 385 ppm.
This is about 100 ppm more than in the water from similar aquifers in
Yucca Flat and Emigrant Valley, which are considered above.
The water
in Frenchman Flat might, on the basis of dissolved solids alone, be
interpreted as having moved southward from Yucca or Emigrant Valleys.
However, the movement of ground water in Yucca Flat has been shown by
Winograd (1962a, b) to be not so much laterally through the alluvium
and tuff as downward through these rocks into the underlying carbonate
rocks and through those rocks to sites of discharge.
The movement of
ground water in Emigrant Valley is imperfectly known, but scanty
evidence suggests that the water table in the vicinity of Groom Lake
slopes : southeastward, not southwestward toward Frenchman Flat.
Hence,
the transfer of substantial quantities of water between the three
valleys, with movement taking place in the tuff and alluvium, seems
unlikely.
The higher dissolved-solids content of the Frenchman Flat
water, therefore, is attributed to longer residence in the rock in that
valley, or to a
relatively greater supply of soluble minerals in the
rock.
Each basin probably is recharged locally from precipitation on
adjacent higher lands.
The water received in this manner may move down-
ward through tuffaceous rocks into the underlying carbonate rocks, as in
Yucca Flat, but it probably does not move in large quantities from the
tuff or tuffaceous alluvium of one of these three basins into similar
rocks of an adjacent basin.
The interbasin movement of ground water
takes place in the carbonate rocks.
58
The water of wells 73-58 and 74-58, Jackass Flats, contains only
197 and 242 ppm, respectively, dissolved solids, and suggest a local
source of recharge.
Both wells tap volcanic rocks.
The higher
dissolved solids are from the well tapping the thicker section of
saturated rock.
Both wells are near the axis of Fortymile Canyon,
where freshening by infiltrating stream water may be effective.
The
ground water at these two wells probably has not traveled far from the
recharge site.
The water from wells 65-53, 66-56, and 69-57, near Lathrop Wells
(fig. 6), has only 294, 310, and 233 ppm, respectively, in dissolved
solids.
Their dissolved-solids content is substantially below the
average for water of the Amargosa Desert (about 465 ppm) 9 but is somewhat higher than the dissolved solids in the waters from wells 73-58
and 74-58 in Jackass Flats (197 and 242 ppm), roughly 10 miles to the
north.
This water, may have enetered the rocks as recharge from runoff
from Fortymile Canyon or as recharge in the high country of Yucca and
Timer Mountains.
The ground water of the Amargosa Desert, as represented by available
analyses, averages about 465 ppm dissolved solids.
The dissolved solids
in 8 to 15 water samples were between 400 and 600 ppm, and they exceeded
700 ppm in 2 samples.
The average is twice that for water in Indian
Spring Valley and substantially greater than the dissolved solids in
most water of the Test Site.
the greatest in the region.
The maximum for the Amargosa Desert is
The dissolved solids point to the Amargosa
Desert, therefore, as the destination to which the ground water may be
going, not as the place from which it comes.
59
WATER MOVEMENTS INFERRED FROM SODIUM DISTRIBUTION
The chemical character of water moving through rocks may be altered
by ion exchange, a process in which one or more ions from the water
solution are exchanged for other ions adsorbed on the rock.
One of these
reactions is the exchange of calcium and/or magnesium dissolved in the
water for sodium or potassium from the rock (Hem, 1959, p. 221).
It is
suggested in another section of this report that the sodium content of
the waters from tuff or tuffaceous alluvium is due in part to solution of
sodium from the rock and in part to the exchange of calcium and
magnesium for sodium.
At any rate, the water that has been in or has
passed through tuffaceous materials generally has a substantial proportior
of sodium and may have but little calcium and magnesium.
The reaction outlined above may be reversible under some circumstances, but the conditions permitting such reversal seem not to exist
in the vicinity of the Nevada Test Site.
To reverse the reaction would
require that the water contain a much greater concentration of sodium
than has yet been found at or near the Test Site.
The normal condition
therefore seems to prevail and the sodium dissolved in ground water
is likely to remain in solution.
If water high in sodium moves out of
tuffaceous materials into sodium-poor materials, such as the carbonate
rocks, it may pick up calcium and magnesium in addition to the solids
already in solution but it will not lose- aodium to the rock.
If a
sodium-potassium water were to become mixed with a calcium-magnesium
water, the result would be a water of mixed chemical character, perhaps
similar to the water from wells 75-73 and 79-69a.
Lack of sodium in
water may be presumed to mean lack of contact of water with rock
containing soluble sodium, tuff included.
60
The presence or absence of sodium in the waters of the Test Site and
vicinity are clues to the ground-water movement.
The distribution of
sodium suggests the following conclusions:
1.
The water in the Paleozoic carbonate rocks underlying the Test
Site is in part recharged by percolation downward through tuff or through
alluvium containing detrital tuff, or both.
The water entering the
carbonate rocks in this manner is generally a sodium-potassium type,
which when added to the calcium-magnesium type already in the rocks
yields a water of mixed chemical character.
2.
The water in the carbonate rocks of the Test Site may be moving
toward the Amargosa Desert, where the water generally is of mixed
chemical character, have a generous amount of sodium, and are more concentrated than those within the Test Site.
Not all the water reaching
the Amargosa Desert, however, need come from the Test Site.
3.
The water of Indian Spring Valley has had little opportunity
for contact with tuff or tuffaceous alluvium, or with another rock
material containing much soluble sodium.
This water probably entered
the rocks as recharge on the upper slopes of the Spring Mountains, which
lie to the south.
The mountains contain extensive outcrops of carbonate
rocks, from which calcium and magnesium could be dissolved.
4.
The water in the carbonate rocks is not moving southward from
the Test Site to Indian Spring Valley.
If it did so, the waters of
Indian Spring Valley would contain more sodium, and also would probably
be higher in dissolved solids.
5.
The ground water in Indian Spring Valley may move northward
toward Frenchman Flat or westward toward Mercury Valley and the Amargosa
61
Desert.
This inference, based solely on the chemical character of the
water, is confirmed by studies of the hydraulic potential, which have
shown the water table to be higher in Indian Spring Valley than in Mercury
Valley or Frenchman Flat (Eakin and others, 1963) .
SUMMARY AND CONCLUSIONS
Sodium-potassium water is found at the Nevada Test Site in aquifers
in tuff and in alluvium containing detrital tuff.
They are found in
Yucca, Frenchman, and Jackass Flats, and in Emigrant Valley.
The water
from springs and those from fractures intersected in tunnels is notably
low in dissolved solids, and this fact suggests nearness of the recharge
areas.
However, the dissolved solids in water from tuffaceous aquifers
tapped by deep wells are not much higher than in the spring and "tunnel"
waters; from this it is inferred that water in such aquifers generally
has not progressed far in their underground travels.
Their chemical
history is relatively uncomplicated.
The water from tuffaceous aquifers in Yucca Flat averages the same
in dissolved solids as the water from similar aquifers in Emigrant Valley.
This fact suggests that movement underground of large quantities of water
from Emigrant Valley into Yucca Flat through these aquifers does not
take place.
The water from tuffaceous aquifers in Frenchman Flat averages higher
in dissolved solids than those in Yucca Flat and Emigrant Valley, and
therefore could have come from those valleys, water chemistry alone being
considered.
However, movement of ground water in tuffaceous rock is
downward into the underlying carbonate rocks and it is concluded that
recharge to the tuffaceous aquifers is derived chiefly from local precipitation in each basin.
62
Calcium-magnesium water is found in limestone and dolomite (carbonate
rocks)
and in alluvium containing, or presumed to contain, detritus of
such rocks.
The waters in Indian Spring Valley are typical calcium-
magnesium type.
A typical calcium-magnesium water low in dissolved solids,
like a typical sodium-potassium water low in dissolved solids, probably
has had only a relatively uncomplicated chemical history.
Water having the characteristics of both the preceding types is
termed water of mixed chemical type.
These may be water from tuffaceous
aquifers that have moved into carbonate rocks (or alluvium with carbonaterock detritus) and there have picked up calcium and magnesium in addition
to solids already in solution.
They may be water from carbonate rocks
that have come in contact with tuff or, more probably, detrital tuff
in alluvium and have picked up sodium by solution or through ion exchange.
They may also be the result of mixing of calcium-magnesium with sodiumpotassium water, but such mixing is probably rare.
Water of mixed chemical type is found in some of the carbonate
rocks tapped by wells within the Nevada Test Site, and suggest that some
of the water recharged to the carbonate rocks passes first through
tuffaceous rocks.
Water of mixed chemical type predominates in the Amargosa Desert.
In general, also, the water of this desert is the most mineralized of
the region.
These facts suggest, therefore, that this water has traveled
farther and Ihas- a more complicated chemical history than others, and
that the Amargosa Desert is a destination for moving ground water.
It
is a discharge area.
The virtual lack of sodium in the waters of Indian Spring Valley
63
is especially significant because sodium dissolved in water generally
remains in water.
Lacking substantial sodium, the water of Indian
Spring Valley has not come from the tuff and tuffaceous alluvium,
or even from the carbonate rocks, within the Nevada Test Site.
More
probably they have been derived from recharge on the upper slopes of
the Spring Mountains, where carbonate rocks crop out.
Their low
content of dissolved solids (average 215 ppm) supports this hypothesis.
Recharge water may also move from the Spring Mountains westward
into the Amargosa Desert.
The calcium and magnesium content of the water,
in percent of total cations, decreases progressively westward from the
mountains in a manner that suggests a meeting with water from the northwest.
Low total solids in three samples from the northern margin of
the Amargosa Desert, near Lathrop Wells, suggest influx of water recharged
nearby, possibly in the high country of the Yucca Mountain-Timber
Mountain area or from surface water in Fortymile Canyon.
In conclusion, the ground water of the Nevada Test Site seems to
be moving into the Amargosa Desert, but not into Indian Spring Valley.
Only a fraction of the water reaching the Amargosa Desert is from the
Test Site.
Large contributions appear to be coming from the Spring
Mountains and from localities to the northwest.
64
REFERENCES CITED
Clebsch, Alfred, Jr., 1961, Tritium-age of ground water at the Nevada
Test Site, Nye County, Nevada:
U.S. Geol. Survey Prof. Paper 424-C,
p. C122-C125.
Clebsch, Alfred, Jr., and Barker, F. B., 1960, Analyses of ground water
from Rainier Mesa, Nevada Test Site, Nye County, Nevada:
U.S. Geol.
Survey TEI-763, 22 p., 3 figs., 2 tables.
Eakin, T. E., Schoff, S. L., and Cohen, Philip, 1963, Regional hydrology
of a part of southern Nevada:
U.S. Geol. Survey TEI-833, 40 p.
Garber, M. S., and Thordarson, William, 1962, Ground-water test well C,
Nevada Test Site, Nye County, Nevada:
U.S. Geol. Survey TEI-818,
79 p.
Healey, D. L., and Miller, C. H., 1962, Gravity survey of the Nevada Test
Site and vicinity, Nye, Lincoln, and Clark Counties, Nevada interim
report:
U.S. Geol. Survey TEI-827, 36 p.
Hem, J. D., 1959, Study and interpretation of the chemical characteristics
of natural water:
U.S. Geol. Survey Water-Supply Paper 1473, 269 p.
Hood, J. W., 1961, Water wells in Frenchman and Yucca Valleys, Nevada Test
Site, Nye County, Nevada:
U.S. Geol. Survey TEI-788, 59 p., 13 figs.,
6 tables.
Houser, F. N., and Poole, F. G., 1959, Lithologic log and drilling information for the marble exploration hole 3, U 15 area, Nevada Test
Site, Nevada:
U.S. Geol. Survey TEM-1031, 22 p.
____1961, Age relations of the Climax composite stock, Nevada Test Site,
Nye County, Nevada:
U.S. Geol. Survey Prof. Paper 424-B, p. B176-B177"
65
Johnson, M. S., and Hibbard, D. E., 1957, Geology of the Atomic Energy
Commission Nevada Proving Grounds Area, Nevada:
U.S. Geol. Survey
Bull. 1021-K, p. 333-384.
Longwell, C. R., 1960, Possible explanation of diverse structural patterns
in southern Nevada, J.n Bradley v. 258-A:
Am. Jour. Sci., p. 192-^203.
Moore, J. E., 1961, Wells, test holes, and springs of the Nevada Test Site
and surrounding area:
U.S. Geol. Survey TEI-781.
___1962, Selected logs and drilling records of wells and test holes
drilled at the Nevada Test Site prior to 1960:
U.S. Geol. Survey
TEI-804, 54 p., 4 figs., 4 tables.
Piper,.A. M., 1945, A graphic procedure in the geochemical interpretation
of water analyses:
Am. Geophys. Union Trans., 25th Ann. Mtg., pt. 6,
p. 914-923.
Price,-C. E., and Thordarson, William, 1961, Ground water test well A,
Nevada Test Site, Nye County, Nevada:
U.S. Geol. Survey TEI-800, 59 p.,
4 figs., 11 tables.
Scott, R. C., and Barker, F. B., 1962, Data on uranium and radium in
ground water in the United States, 1954 to 1957:
U.S. Geol. Survey
Prof. Paper 426, 115 p., 2 pi., 7 figs.
U.S. Public Health Service, 1946, Public Health Reports:
___1962, Drinking water standards:
Reprint 2697.
Pub^ 956, 61 p.
Walker, G. S., 1962, Ground water in the Climax stock, Nevada Test Site,
Nye County, Nevada:
20 tables.
U.S. Geol. Survey TEI-813, 48 p., 11 figs.,
66
Winograd, I. J., I962a, Interbasin movement of ground water at the Nevada
Test Site:
U.S. Geol. Survey TEI-807, 12 p., 4 figs.
___1962b, Interbasin movement of ground water at the Nevada Test Site:
U.S. Geol. Survey Prof. Paper 450C, p. C108-C111.
73
APPENDIX B.-^ELECTED CHEMICAL ANALYSES OF WATERS FROM SPRINGS AND
TUNNELSt, IN PARTS PER MILLION AND EQUIVALENTS PER MILLION (IN PARENTHESES) ,
BY THE U.S. GEOLOGICAL SURVEY
Chemical analyses for waters of springs in and near the Nevada Test
Site, including repetitive analyses as available, were reported by Moore
(1961, table 5a).
each spring.
The table below includes only the latest analysis for
This is the only analysis for some springs, and, therefore is
a repetition of the analysis published previously, but for others it is an
analysis made since the previous publication.
In all cases the analysis
given below is the one on which the chemical diagram shown in this report
is based; in no case does the latest analysis differ greatly from previous
analyses of water from the same source.
Analyses representing a few
springs in the Amargosa Desert and Indian Spring Valley are included.
Chemical analyses for waters from fractures intersected in the U-12-b
tunnel in Rainier Mesa and from drill holes in the tunnel were reported
by Clebsch and Barker (1960, table 2A).
Only six additional samples from
such sources have been analyzed subsequently, and these are reported below.
The springs in the Nevada Test Site are fed by perched zones of
saturation and therefore do not represent directly the regional relationships that are the subject of this paper.
Accordingly, they are omitted
from figure 1 in the interest of simplicity.
Their locations can be
determined approximately from the numbers assigned to them, which consist
of the first two digits of the north coordinate followed, after a hyphen,
by the first two digits of the east coordinate.
"Numbering system" for further explanation.)
(See the section on